A Catalog of Galaxy Clusters Observed by XMM-Newton

Aims: We present a uniform catalog of the images and radial profiles of the temperature, abundance, and brightness for 70 clusters of galaxies observed by XMM-Newton. Methods: We use a new "first principles" approach to the modeling and removal of the background components; the quiescent particle background, the cosmic diffuse emission, the soft proton contamination, and the solar wind charge exchange emission. Each of the background components demonstrate significant spectral variability, several have spatial distributions that are not described by the photon vignetting function, and all except for the cosmic diffuse emission are temporally variable. Because these backgrounds strongly affect the analysis of low surface brightness objects, we provide a detailed description our methods of identification, characterization, and removal. Results: We have applied these methods to a large collection of XMM-Newton observations of clusters of galaxies and present the resulting catalog. We find significant systematic differences between the Chandra and XMM-Newton temperatures.Comment: Accepted for publication in A&A, 55 pages with 42 figure

Modeling the Local Warm/Hot Bubble

In this paper we review the modeling of the Local Bubble (LB) with special emphasis on the progress we have made since the last major conference "The Local Bubble and Beyond (I)" held in Garching in 1997. Since then new insight was gained into the possible origin of the LB, with a moving group crossing its volume during the last 10 - 15 Myr being most likely responsible for creating a local cavity filled with hot recombining gas. Numerical high resolution 3D simulations of a supernova driven inhomogeneous interstellar medium show that we can reproduce both the extension of the LB and the OVI column density in absorption measured with FUSE for a LB age of 13.5 - 14.5 Myr. We further demonstrate that the LB evolves like an ordinary superbubble expanding into a density stratified medium by comparing analytical 2D Kompaneets solutions to NaI contours, representing the extension of the local cavity. These results suggest that LB blow-out into the Milky Way halo has occurred roughly 5 Myr ago.Comment: 8 pages, 3 figures, to appear in the proceedings of "The Local Bubble and Beyond II", Philadelphia, USA, April 21-24, 200

The EPIC-MOS Particle-Induced Background Spectrum

We have developed a method for constructing a spectrum of the particle-induced instrumental background of the XMM-Newton EPIC MOS detectors that can be used for observations of the diffuse background and extended sources that fill a significant fraction of the instrument field of view. The strength and spectrum of the particle-induced background, that is, the background due to the interaction of particles with the detector and the detector surroundings, is temporally variable as well as spatially variable over individual chips. Our method uses a combination of the filter-wheel-closed data and a database of unexposed-region data to construct a spectrum of the "quiescent" background. We show that, using this method of background subtraction, the differences between independent observations of the same region of "blank sky" are consistent with the statistical uncertainties except when there is clear evidence of solar wind charge exchange emission. We use the blank sky observations to show that contamination by SWCX emission is a strong function of the solar wind proton flux, and that observations through the flanks of the magnetosheath appear to be contaminated only at much higher solar wind fluxes. We have also developed a spectral model of the residual soft proton flares, which allows their effects to be removed to a substantial degree during spectral fitting

Fragmentation Phase Transition in Atomic Clusters II - Coulomb Explosion of Metal Clusters -

We discuss the role and the treatment of polarization effects in many-body systems of charged conducting clusters and apply this to the statistical fragmentation of Na-clusters. We see a first order microcanonical phase transition in the fragmentation of $Na^{Z+}_{70}$ for Z=0 to 8. We can distinguish two fragmentation phases, namely evaporation of large particles from a large residue and a complete decay into small fragments only. Charging the cluster shifts the transition to lower excitation energies and forces the transition to disappear for charges higher than Z=8. At very high charges the fragmentation phase transition no longer occurs because the cluster Coulomb-explodes into small fragments even at excitation energy $\epsilon^* = 0$.Comment: 19 text pages +18 *.eps figures, my e-mail adress: [email protected] submitted to Z. Phys.

The Ursinus Weekly, January 22, 1945

Y weekend closes with vespers talk by Dr. A. N. Sayres • Cast of drama is new to Ursinus audience but has experience • Sailors lured to destruction by Lorelei; Ursinus version to have canteen theme • Tickets to be out for Navy ball soon • V-12 men give Johnson transfusions at hospital • Curtain Club lists intra-club groups • Ahoy attends party as pre-meds celebrate • Final intramural contests held by men\u27s, women\u27s debate clubs • Canterbury Club elects Delheim as president; draws up board • Dr. Lentz represents reformed at Cleveland peace conference • Y discussion group is cancelled • Lutherans to organize Thursday • In lab for one day, or why profs get gray • Bears are Madding crowd • Wrestlers drop first meet, 28-10, to Swarthmore • Ursinus narrows margin to six points but falls before Albright team, 65-50 • Twelve girls receive varsity basketball suits as season approacheshttps://digitalcommons.ursinus.edu/weekly/1696/thumbnail.jp

The Ursinus Weekly, January 15, 1945

Thespians to give mystery drama of unusual record • Stardusters, band plan solid swing musical • Discussion, dance to feature \u27Y\u27 activities for this weekend • Students give views on racial prejudice • Ball chairmen plan theme and banquet • Stilla lookin advises Lorelei lorn as local Sadie Hawkins\u27 Day approaches • Carney\u27s talk advises correction of troubles • Debate clubs hold intramural contest • New Yeoman has seen action in 4 invasions • Friday is Lantern deadline • Men\u27s student council sponsors evening dancing in rec center • Rev. Platts explains prayer book at meeting of Canterbury Club • Ethel Fehrle \u2746, is engaged to Lt. Doane, Penn graduate • Henry Solon, artist, addresses meeting of AAUW Wednesday • Dr. Gerhart addresses Lutherans • Dorms without water; seek H-2-O formula • Suflas and Dearden make Harvard team • Ursinus holds Penn in last two periods; but lose here, 65-52 • Bears outscore Drexel, 55-36, on Philadelphia court Friday • Girls receive awards for hockey at banquet • Curtain Club announces committees for production of Night Must Fall • Derr, Stine battle ends in deadlock • Betty Yeager to review Brooke\u27s World of Washington Irving • Newman studies communismhttps://digitalcommons.ursinus.edu/weekly/1695/thumbnail.jp